Thermal Stability Of Nanocomposites Research Articles

Evaluation of the resistance to bacterial growth of star-shaped poly(ε-caprolactone)-co-poly(ethylene glycol) grafted onto functionalized carbon nanotubes nanocomposites

Nanocomposites of functionalized carbon nanotubes (CNTsf) as nanofillers, and a copolymer of star-shaped poly(ε-caprolactone) (stPCL) and poly(ethylene glycol) (PEG) as a polymeric matrix were synthesized, characterized, and their resistance to the growth of Staphylococcus aureus and Pseudomonas aeruginosa was evaluated. CNTsf contain hydroxyl, carboxyl and acyl chloride groups attached to their surface. Nanocomposites were prepared by mixing CNTsf to a solution of stPCL-PEG copolymer. Raman and FT-IR spectroscopies confirm the functionalization of carbon nanotubes (CNTs). Star-shaped PCL-PEG copolymer was characterized by Gel permeation chromatography (GPC), and 1H-NMR and 13C-NMR spectroscopies. X-ray photoelectron spectroscopy (XPS) shows that CNTsf are grafted to the stPCL-PEG copolymer. Crystallization behavior of the nanocomposites depends on the amount of CNTsf used in their preparation, detecting nucleation (nanocomposites prepared with 0.5 wt.% of CNTsf) or anti-nucleation (nanocomposites prepared with 1.0 wt.% of CNTsf) effects. Young’s Moduli and thermal stability of nanocomposites were higher, but their resistence to the proliferation of Staphylococcus aureus and Pseudomonas aeruginosa was lower than the observed for their pure polymer matrix.

Synergistic Effect of Micro and Nano Fillers on Mechanical and Thermal Behavior of Glass-Basalt Hybrid Nano Composites

This article deals with the combined effect of micro and nano fillers on mechanical, thermal and morphological behavior of glass-basalt hybrid composites (GB). Three material systems were selected for the study: glass-basalt fiber reinforced 80 wt. % PA66 – 20 wt. % PTFE blend (GB), GB/Micro fillers (MoS2, SiC, Al2O3) (GBM) and GBM/nano fillers (TiO2) (GBN). It has been revealed from the experimentation that the effect of micro fillers deteriorated the mechanical behavior of micro composites (GBM). But the combined effect of micro and nano fillers slightly impaired the mechanical behavior of nano composites. The synergistic effect of micro and nano fillers constrained the loss of strength of nano composites. But the impact strength of nano composites has been improved due to hybrid fillers effect. The hybrid effect of fillers significantly improved the thermal stability of nano composites. Further, it is observed from the morphology that the fractured surfaces were characterized by fiber pull out and fiber overlapping, severe deformation and agglomeration of nano particles.

NiFe2O4/Poly(1,6-heptadiyne) Nanocomposite Energy-Storage Device for Electrical and Electronic Applications.

In present study, we have synthesized intrinsically conductive poly(1,6-heptadiynes) via cyclopolymerization technique, and further it is composited with the NiFe2O4 to fabricate pellet for electrical and electronic applications. The synthesized polymer I–V characteristics were obtained by two-probe measurement technique. The results suggest that the high current density of the synthesized polymer was in the range of 1.2 × 10–5–3.1 × 10–5 S/cm, which attributes to the potentially induced hoping charge-carrier mechanism within the conjugated poly(1,6-heptadiynes). NiFe2O4 and NiFe2O4/poly(1,6-heptadiynes) composite pellets were fabricated by utilizing hydraulic pelletizer. The sample’s electrical measurements were performed via broad-band dielectric impedance spectroscopy, wherein the composite permittivity was about ε = 45 (100 Hz to 10 kHz), which attributes to the NiFe2O4 and poly(1,6-heptadiynes) phases; further, this describes the capacitance, which improved from 0.3 to 0.1 pf at 1 kHz. Also, these results suggest the reduced equivalent series resistance (72.1–1 MHz), which attributes to the incorporated intrinsically conducting poly(1,6-heptadiynes). Thus, the reduced dissipation factor (DF = 0.0032) was observed from impedance characteristics of a nanocomposite. Moreover, the improved Q-factor was observed, which was about 8.1–310 at 1 kHz. The resistance and capacitance time constant was also computed to be about 0.29 μs at 1 kHz for NiFe2O4/poly(1,6-heptadiynes) nanocomposite. Furthermore, the nanocomposite-enabled capacitor gravimetric energy density and power densities were calculated to be about 0.00575 mJ/g and 9.91 W/g, respectively. Additionally, thermal threatening, that is, heat generated within the capacitor, Ploss is also estimated for the nanocomposite capacitor, which improved from 0.0006 to 8.9 × 10–6, and these results suggest improved nanocomposite thermal stability. Further, the delineated quantities were compared to the commercially available configurations of tantalum hybrid capacitors and Al and Ta electrolytic capacitors, including carbon electrochemical capacitors, which suggest that the reported nanocomposites could be a suitable candidate for electrical and electronic applications.

Effect of mesoporous SBA-15 silica on the thermal stability of isotactic polypropylene based nanocomposites prepared by melt extrusion

The influence of mesoporous SBA-15 on the thermal stability of nanocomposites with isotactic polypropylene has been evaluated in detail, both under inert and air conditions, by performing dynamic weight loss measurements and by tracking the evolution of degradation species in materials prepared by melt extrusion. A superior thermal stability has been found in the composites, both under nitrogen and air, compared with that observed in the pristine PP. An almost identical effect has been found under those two atmospheres, in spite that the mechanisms involved in both of them are completely different. The rheological characteristics of these materials turn out the driving aspect in the observed thermal behaviour, prevailing on other specific detrimental parameters.

Green esterification: A new approach to improve thermal and mechanical properties of poly(lactic acid) composites reinforced by cellulose nanocrystals

ABSTRACTCellulose nanocrystal (CNCs)‐reinforced poly(lactic acid) (PLA) nanocomposites were prepared using twin screw extrusion followed by injection molding. Masterbatch approach was used to achieve more efficient dispersion of CNCs in PLA matrix. Modified CNCs (b‐CNCs) were prepared using benzoic acid as a nontoxic material through a green esterification method in a solvent‐free technique. Transmission electron microscopy images did not exhibit significant differences in the structure of b‐CNCs as compared with unmodified CNCs. However, a reduction of 6.6–15.5% in the aspect ratio of b‐CNCs was observed. The fracture surface of PLA‐b‐CNCs nanocomposites exhibited rough and irregular pattern which confirmed the need of more energy for fracture. Pristine CNCs showed a decrease in the thermal stability of nanocomposites, however, b‐CNCs nanocomposites exhibited higher thermal stability than pure PLA. The average storage modulus was improved by 38 and 48% by addition of CNCs and b‐CNCs in PLA, respectively. The incorporation of b‐CNCs increased Young's modulus, ultimate tensile stress, elongation at break, and impact strength by 27.02, 10.90, 4.20, and 32.77%, respectively, however, CNCs nanocomposites exhibited a slight decrease in ultimate strength and elongation at break. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46468.

Synthesis, Characterization and Their Antimicrobial Activities of Boron Oxide/Poly(Acrylic Acid) Nanocomposites: Thermal and Antimicrobial Properties

Abstract Boron oxide (B2O3)/Poly(acrylic acid) (PAA) nanocomposites were synthesized by solution intercalation method, and characterized by Fourier transform infrared spectroscopy (FTIR-ATR), transmission electron microscopy (TEM), X-ray diffraction and thermogravimetric analysis (DTA/TG). The effect of boron oxide amount on the thermal stability of nanocomposites was investigated. Moreover, the antimicrobial activities of them were also determined by the serial dilution method against E. coli and S. aureus. XRD analysis showed that boron oxide was homogenously dispersed in polymer matrix; FTIR-ATR that there was interaction between PAA and boron oxide; and TEM that boron oxide particles had spherical structure, and dispersed in nano size in polymer matrix; DTA/TG that the thermal stability of polymers increased with the adding of boron oxide into polymer matrix, and changed the decomposition mechanism of PAA. B2O3/PAA nanocomposites exhibited higher decomposition temperature. The decomposition mechanisms of PAA and its nanocomposites occurred through three decomposition steps; dehydration, decarboxylation and chain scission. B2O3/PAA nanocomposites showed greater antimicrobial activity with increasing B2O3 amount.

High energy density supercapacitive material based on a ternary hybrid nanocomposite of cobalt hexacyanoferrate/carbon nanofibers/polypyrrole

In the proposed work, we present a novel, high performance ternary hybrid nanocomposite material based on cobalt hexacyanoferrate/carbon nanofibers/polypyrrole (CoHCF/CNF/PPY). The nanocomposite is fabricated by in situ oxidative polymerization of pyrrole in presence of CoHCF and CNF utilizing simple, cost effective and environmentally friendly approach. The structural and elemental characterizations of the nanocomposite are carried out by various characterization techniques which revealed formation of PPY layer on CNF surface to which CoHCF nanoparticles are linked. Also, the thermal stability of nanocomposite is found to be increased due to presence of CNF backbone. The electrochemical performances of the nanocomposite are investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques, which resulted into specific capacitance of 512 F g−1 at the current density of 0.5 A g−1. Moreover, it exhibits notable energy density of 102 W h. kg−1 and power density of 628 W kg−1. It also shows capacitive retention up to 87.8% after 2000 cycles indicating excellent cyclic stability. The structural stability of CoHCF framework is maintained due to ion diffusion through the cavities and its combination with interlinking network of PPY chains on the surface of CNF enhances electron transport. This charge storage mechanism is responsible for improved charge storage capacity resulting into high energy density. Thus, proposed ternary hybrid nanocomposite of CoHCF/CNF/PPY can be considered to overcome the gap between supercapacitors and batteries, thus can serve as a promising candidate for the future energy storage technologies.

Synthesis and Characterization of Sunflower Oil-based Polysulfide Polymer/Cloisite 30B Nanocomposites

In current work, halogenated sunflower oil was reacted with Na2S3 to produce sunflower oil-based polysulfide polymer. Cloisite 30B as organomodified nanoclay was used in different contents to investigate its effect on the properties of the synthesized polymer. All nanocomposites were prepared via in situ polymerization method in aqueous media. Fourier Transform-InfraRed (FT-IR) spectroscopy revealed the inclusion of nanoclay in a polymeric matrix.X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) were used to study the degree of intercalation/exfoliation of nanoplatelets in matrices. Proton Nuclear Magnetic Resonance (1H NMR) was utilized to study the molecular weight of synthesized polymers. Thermal stability of nanocomposites was determined by means of Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) was used to investigate thermophysical properties. According to results, nanocomposite with 1 wt. % of Cloisite 30B showed an exfoliated morphology whereas the higher amount of nanoclay resulted in intercalated nanoplatelets with different degrees of intercalation. Also, adding more Cloisite 30B nanoplatelets led to more decrease in molecular weight. After the introduction of nanoclay into nanocomposites structure and increasing its content, the thermal stability of nanocomposites was improved whereas no significant improvement of thermal stability was observed by increasing clay content from 3 to 5 wt. %. Also, all samples showed only the glass transition temperature (Tg) and no distinct peak related to melting was observed. Adding more nanoclay resulted in higher Tg value due to the confinement effect of nanoplatelets.

Effect of Silver Doped Zinc Oxide as Nanofiller for the Development of Biopolymer Nanocomposites from Chitin and Cashew Gum

Nanocomposites based on chitin (CT) and cashew gum (CG) with different concentrations of silver doped zinc oxide nanoparticles (Ag–ZnO) were prepared and characterized by FTIR, UV, XRD, TEM, SEM, DSC, TGA, electrical conductivity measurements. FTIR spectra showed that the characteristic absorption band of the blend was shifted to a higher frequency in nanocomposites, indicating the intermolecular interaction between the blend and nanoparticles. The change in the UV absorption of nanocomposites relative to that of pure blend indicated the successful encapsulation of crystalline metal oxide nanoparticles in the blend matrix. XRD patterns showed that the diffraction peak of the composites were shifted near to the metal oxide peak which indicated that the surface of Ag–ZnO was perpendicular to CT/CG and changed from a semi-crystalline nature to a crystalline structure. The morphological analysis using SEM and TEM showed a uniform attachment of nanoparticles within the CT/CG blend. DSC analysis showed the increased glass transition temperature by the addition of nanoparticles. Thermal stability of nanocomposites was higher than the blend and thermal stability increased with an increase in the content of nanoparticles. The different electrical properties such as AC conductivity and dielectric behaviour of the composites were increased with an increased loading of nanoparticles.

The influence of silica nanoparticles on thermal degradation and mechanical properties of nanocomposites based on aliphatic polyurethanes

Nanocomposites based on aliphatic polyurethanes have recently attracted a lot of attention regarding economical and ecological aspects, due to their improved thermal and mechanical properties. The aim of this paper was to investigate the influence of silica nanoparticles, differing in size and specific surface, on thermal stability and degradation, lifetime and mechanical characteristics of the obtained nanocomposites. Two series of nanocomposites based on aliphatic polyurethanes were obtained by using a single-step procedure and by addition of silica nanoparticles of types A380 or N999 at different loadings (0,0 0.15, 0.5, 1,0 and 3.5 wt.%). It was found that the increase in heating rate caused shifting of the onset temperature to higher values (from 283 to 312 ?C). According to the shape of DTG curves, it was observed that the degradation mechanism of prepared nanocomposites consists of two overlapping processes, related to the scission of hard and soft building blocks. Based on DTG results, the addition of larger N999 silica nanoparticles induced lower thermal degradation, shifting the maximum rate temperatures of the first and second degradation stages to lower values, and caused the change in the degradation mechanism. Addition of smaller silica nanoparticles (A380) did not significantly affect the mechanism of the degradation reaction, indicating homogeneity of the obtained nanocomposites. The presence of A380 nanoparticles improved thermal stability of nanocomposites, by increasing the onset temperature from 286 ?C for the pristine elastomer to 303 ?C for the sample containing 3.5 wt.% of silica. Existence of interactions of A380 silica nanoparticles with hard and soft phases was observed, based on the increase in the maximum rates of the first and second degradation steps. The activation energy of thermal degradation of polyurethanes modified with A380 silica nanoparticles was obtained by using the Flyn-Wall and Toop models. Dependence of the activation energy and the lifetime of nanocomposites based on aliphatic polyurethanes on the silica content were estimated. The highest Ea values (determined for 1 and 5 % weight loss) were found for nanocomposites containing 0.5 and 0.15 wt. % of A380 silica nanoparticles (121 and 161.2 kJ/mol). A negative effect of the silica addition on mechanical properties of nanocomposites was observed. The polyurethanes containing smaller SiO2 particles (A380) had a higher tensile strength, elongation at break and hardness as compared to the elastomers filled with larger silica nanoparticles (N999).

Study of the morphological and thermal properties of polystyrene nanocomposites based on modified halloysite nanotubes with styrene-maleic anhydride copolymers

In this study, the melt blending method was used to prepare the polystyrene/halloysite nanotubes (PS/HNTs) nanocomposites instead of in-situ bulk polymerization of styrene monomer in the presence of HNTs. Surface modification of HNTs with styrene-maleic anhydride copolymers (SMA) was performed in THF medium to improve the HNTs distribution and compatibility in the PS matrix. PS/HNTs nanocomposites were prepared in a twin-screw micro compounder containing 5, 10, and 15wt.% of nanoclays. The influences of the surface modification of HNTs on the properties of the nanocomposites were studied by XRD, SEM, DSC, TGA, and tensile test. The SEM images showed that the modified HNTs samples were uniformly distributed in the PS matrix compared to the pristine HNTs. The thermal stability of nanocomposites was also improved by increasing of modified HNTs content. Consequently, the surface modification increased the dispersion of HNTs in the PS nanocomposites prepared by melt blending method.

Thermal and morphological characterization of highly porous nanocomposites for possible application in potassium controlled release

The use of fertilizer and water availability are essential factors limiting the agricultural production. The controlled release technology is very promising because it allows the maintenance of fertilizer concentrations within an ideal range avoiding inefficiency and toxicity problems, minimizing the environmental impacts and improving their efficiency. In this context, the nanostructured hydrogels appear as a possible carrier vehicle for these controlled release systems due to their inherent properties, such as biodegradability, low toxicity, and cost, rapid absorption and desorption controlled capacity of water and solutes. In this work, we performed the synthesis of nanostructured hydrogels based on poly(methacrylic acid) (PMAA)/Cloisite-Na+ via free radical polymerization. SEM images indicated a similarity in the basic structure of all nanocomposites. The porous diameter of the hydrogels increased with increasing of nanoclay content. EDS analysis showed the ions belonging to nanoclay present in the nanocomposites, confirming the formation of true nanocomposites. TG–DTG and DSC techniques confirmed an improvement in the thermal stability of nanocomposites caused by the addition of nanoclay. For instance, the degradation initial temperature of the hydrogel was increased from 198.5 to 203.5 °C, and inversely, the degradation rate of the 2° thermal event was decreased from 0.694 to 0.472% min °C−1, when the nanoclay was increased from 0 to 20 mass/%. Moreover, the controlled release investigation showed an improvement in the release time and quantity of the fertilizer released with nanoclay content. This result is very required for this specific application.

Poly(ε-caprolactone) filled with polydopamine-coated high aspect ratio layered double hydroxide: Simultaneous enhancement of mechanical and barrier properties

Inspired by the versatile adhesion capability of marine adhesive proteins, core-shell structured polydopamine-coated layered double hydroxide (LDH@PDA) were prepared successfully by in-situ growing PDA on the surface of MgAl-LDH with a high aspect ratio. LDH@PDA/poly(ε-caprolactone) (PCL) nanocomposites were prepared by blending LDH@PDA and pure PCL via solution casting method to obtain homogeneous films. The results of thermal analysis confirmed that LDH@PDA can act as a nucleating agent. And thermal stability of nanocomposites was improved due to core-shell structured LDH@PDA. With incorporation of as low as 1wt% of LDH@PDA, a 20% increase in tensile strength (41.1MPa), 26% increase in elongation at break (772%) and 26% reduction in the oxygen relative permeability were achieved. The improvement in the mechanical and gas barrier properties of nanocomposites at low filler loading was attributed to the strong interfacial interaction of LDH@PDA wtih the PCL matrix.

Hydrogel nanocomposites based on chitosan-g-polyacrylamide and silver nanoparticles synthesized using Curcuma longa for antibacterial applications

Hydrogel nanocomposites based on chitosan-g-polyacrylamide and silver nanoparticles (Cs-g-PAAm/AgNPs) were developed by simple, cost effective, and eco-friendly process at room temperature. First, the hydrogels were prepared via grafting copolymerization and crosslinking of acrylamide (AAm) onto chitosan (Cs) with various weight ratios, using potassium persulfate as initiator and N,N′-methylenebisacrylamide as crosslinker, and then hydrolyzed to achieve materials with uppermost swelling properties. Finally, the AgNPs were biosynthesized and entrapped into hydrogels as templates using aqueous silver nitrate as precursor and Curcuma longa tuber extract as both reducing and stabilizing agents. The influences of the templates and the silver precursor concentrations on the AgNP formation and the properties of the elaborated nanocomposites were investigated. The UV–visible spectroscopy has confirmed the occurrence of the nanosilver particle formation, while the X-ray diffraction analysis has evidenced their face-centered cubic crystalline phase. The inductively coupled plasma analysis has revealed that the extent of AgNPs into the network increases by a decrease in Cs weight ratios and an increase in AgNO3 concentrations. Transmission electron microscope images have showed a spherical shape of AgNPs with average sizes <26 nm. Interactions between hydrogel functional groups and those of proteins extracted from C. longa, which are probably the capping ligands of the AgNPs, were suggested from Fourier transform-infrared spectroscopy. Slight enhance in thermal stability of nanocomposites was noticed from thermogravimetric analysis. Besides, the swelling and retention capacities were affected by both Cs and AgNP contents. Furthermore, the swelling kinetics was found to obey the second-order model with non-Fickian diffusion. The antibacterial activity against Staphylococcus aureus and Escherichia coli bacteria was examined by both zone inhibition and dynamic shake flask methods and the results have showed an efficient activity of AgNP-loaded hydrogels with a maximum of killing ratio of 99.99%. Finally, it is suggested that the optimized hydrogel nanomaterials can be candidates for bio-applications.

Polylactide/cellulose nanocrystals: The in situ polymerization approach to improved nanocomposites

The in situ polymerization of l-lactide in the presence of various amounts of cellulose nanocrystals (CNC) is described. CNC was prepared efficiently by acidic hydrolysis of cotton linters. Molecular weight, morphology, thermal, mechanical and crystallization properties of the PLA-CNC nanocomposites were evaluated. From size-exclusion chromatography (SEC) analysis, the actual occurrence of chemical bond between CNC and PLA can be assessed. The effect of CNC has been evaluated through differential scanning calorimetry (DSC) analysis, which highlights the probable formation of α′ crystals in the obtained materials. More importantly, from thermogravimetric analysis (TGA) a marked improvement in thermal stability of nanocomposites has been demonstrated, with respect to standard PLA and to previously described PLA-CNC blends. Nanocomposites show also an improvement in rheological properties with respect to standard PLA. In particular, storage modulus greatly increases, indicating a reinforcing effect of CNC. The described in situ synthetic methodology allows an optimal compatibilization between the two entities (PLA and CNC), facing one of the major problems inherent to the preparation of nanocomposites. It leads furthermore to remarkably improved thermal and rheological properties of the obtained materials.

Production of bionanocomposites based on poly(vinyl pyrrolidone) using modified TiO2 nanoparticles with citric acid and ascorbic acid and study of their physicochemical properties

Poly(vinyl pyrrolidone) (PVP) is a biocompatible, biodegradable, and hydrophilic polymer that has many applications in different fields. Reinforced PVP nanocomposites (NCs) containing titanium dioxide nanoparticles (TiO2 NPs) were prepared through solution casting method. To achieve better distribution of NPs in the polymeric bed, surface modification of NPs is essential. Citric acid (CA) and ascorbic acid (vitamin C) (VC) biomolecules were used as surface modifiers. Modified TiO2 NPs were incorporated in the PVP bed. X-ray diffraction, Fourier transforms infrared, transmission electron microscopy (TEM), and field-emission scanning electron microscopy were used to explore the resulted PVP/TiO2–CA–VC NCs. Thermal gravimetric analysis (TGA) was used to investigate thermal stability of PVP/TiO2–CA–VC NCs. TEM results showed that modified NPs were well distributed in the biopolymeric bed. TGA confirmed that thermal stability of NCs has been improved.

Dynamic Mechanical Analysis of Carbon Nanotube-Reinforced Nanocomposites

BackgroundTo predict the mechanical properties of multiwalled carbon nanotube (MWCNT)–reinforced polymers, it is necessary to understand the role of the nanotube-polymer interface with regard to load transfer and the formation of the interphase region. The main objective of this study was to explore and attempt to clarify the reinforcement mechanisms of MWCNTs in epoxy matrix.MethodsNanocomposites were fabricated by adding different amounts of MWCNTs to epoxy resin. Tensile test and dynamic mechanical analysis (DMA) were conducted to investigate the effect of MWCNT contents on the mechanical properties and thermal stability of nanocomposites.ResultsCompared with the neat epoxy, nanocomposite reinforced with 1 wt% of MWCNTs exhibited an increase of 152% and 54% in Young's modulus and tensile strength, respectively.ConclusionsDynamic mechanical analysis demonstrates that both the storage modulus and glass transition temperature tend to increase with the addition of MWCNTs. Scanning electron microscopy (SEM) observations reveal that uniform dispersion and strong interfacial adhesion between the MWCNTs and epoxy are achieved, resulting in the improvement of mechanical properties and thermal stability as compared with neat epoxy.

Nanostructured phenolic matrices: Effect of different nanofillers on the thermal degradation properties and reaction to fire of a resol

SummaryIn this work, the effect of 6 different fillers as a nanomodifier of phenolic matrix was evaluated in thermal stability and reaction to fire. The chosen nanoparticles were montmorillonite, silica, carbon black, and 3 carbides—boron, silicon, and zirconium carbides. The nanofillers were mechanically dispersed in the matrix, and the dispersion and distribution of the nanosized particles in the matrix was evaluated by transmission electron microscopy. The thermal stability of nanocomposites was investigated by thermogravimetric analysis both in nitrogen and in air while the thermal combustion properties were measured using a microscale combustion calorimeter. The experimental data highlighted the remarkable effects of nanoboron carbide on the thermal properties it can confer to the phenolic matrix. Rheological behavior of the blends was also investigated to evaluate the effect of the different fillers on the viscosity of the nanostructured matrices.

Effects of Solvents on Structure, Morphology and Thermal Stability of Polystyrene-HNTs Nanocomposites by Ultrasound Assisted Solution Casting Method

Polymer-clay nanocomposites are extensively investigated as they are economical in comparison with other nanofillers and drastically enhances various physical and engineering properties of polymers. Among various clays used for polymer-nanocomposites, Halloysite nanotubes (HNTs) have gained tremendous attention as they have unique structure and properties. In the present work we have successfully synthesised polystyrene-HNT nanocomposites by ultrasound assisted solution intercalation method. In this method solvent plays a very crucial role in enhancing the overall properties of resultant nanocomposites as arrangement of filler in the polymer matrix depends upon how well the solvent is able to disperse filler which inturn enhances polymer properties. Hence in this work solvents toluene, benzene, chloroform, dichoromethane (DCM), tetrahydrofuran (THF) and carbontetrachloride (CCl4) were used for synthesis of nanocomposites and effect of these solvent on structure, morphology and thermal stability of nanocomposites was investigated. As per the characterization analysis, toluene was found to be the best solvent for synthesis of nanocomposites with enhanced properties and use of ultrasound aided in uniform distribution of clay in polymer matrix. Increase in basal spacing on sonication was revealed by x-ray diffraction (XRD) analyses. Scanning electron microscopy (SEM) results revealed uniform dispersion of filler inside the matrix on using acoustic cavitation as it promotes proportionate distribution of filler into the polymer matrix. Fourier transform and infrared (FT-IR) results confirmed encapsulation of HNTs into polymer. Differential scanning calorimetry (DSC) reports illustrated increase in glass transition temperature (Tg) on incorporating HNTs.

Investigation of thermal, mechanical behavior, and contact angle measurements of poly(vinyl chloride) based nanocomposite films containing coated CuO nanoparticles with thiamine

In this work, poly(vinyl chloride) (PVC)/CuO-VB1(vitamin B1) nanocomposite (NC) films were prepared by solution casting method. For this purpose, CuO nanoparticles (NPs) were chosen as an appropriate nano-filer to incorporate into the PVC matrix. To prevent aggregation and make NPs more compatible with the polymer matrix, surface modification of NPs was performed. Thiamine (vitamin B1) is a biological molecule used as a bio-safe modifier. Then, PVC/CuO-VB1 NCs were obtained by addition of different weight percentages (3, 5, and 7 wt%) of modified NPs into the PVC matrix under ultrasonic irradiation. The prepared NCs were examined using various techniques. The results confirmed that relative changes in the obtained data and morphology, as the concentration of nano-filler was increased. Furthermore, incorporating the NPs into PVC caused an increase in thermal stability of NCs as compared to neat PVC. FE-SEM and TEM morphological analysis showed good compatibility of modified CuO with the PVC matrix. The contact angle results verified that hydrophilicity of NCs increased by adding fillers into the polymer matrix. Finally, addition of NPs into the PVC matrix had influenced on optical absorption and mechanical behaviors of PVC.